In conventional network management, a router employs an interface in a communication path, or a route, when the interface is stable. If the interface rapidly changes its link state to and from up and down within a short period of time, the interface is referred to as “flapping,” and the flapping interface sends out an excessive amount of route adjust messages. The router dampens the flapping interface by filtering out the route adjust messages from the flapping interface, and does not employ the dampened interface in further routing. Consequently, the interface is either up or down, and an error rate of the interface is not evaluated in conventional network management.